Fix xtables.lock race condition between weave and kube-proxy.

[louismunro]

Creates a new prog/weave-kube/weave-daemonset-k8s-1.8.yaml with type "FileOrCreate" based on the existing 1.7 one.
I tried to take care of the release and testing too but I might be missing something. Feel free to correct me if that's the case.

Fixes #3351

[louismunro]

:-(
circle-test-smoke seems to expect a secret key.
Was I meant to provide it as part of the PR?

[murali-reddy]

Was I meant to provide it as part of the PR?

No, There are limitation w.r.t secrets to run CI against forked repo PR's. I pushed the branch to main repo. CI looks good.

[bboreham]

Why is this different to #3134 ?

[bboreham]

Oh, I see, it's FileOrCreate, just as you said.

[bboreham]

Thanks!

BTW, just to check, I did:

$ diff weave-daemonset-k8s-1.7.yaml weave-daemonset-k8s-1.8.yaml 
206a207
>                 type: FileOrCreate